The present invention disclosed herein relates to a semiconductor device and a method for manufacturing the same.
A copper wiring is generally used to form a circuit pattern in a semiconductor device. A diffusion bather for preventing copper from diffusing to a substrate is formed on the substrate before electroplating copper on the substrate, and a seeding layer for stably forming copper on the substrate is formed on the diffusion barrier. That is, typically, a double thin film of a diffusion layer such as a TiN diffusion layer and a seeding layer such as a Ru seeding layer is formed to form a copper wiring.
A typical double thin film process causes an increase in the cost of a manufacturing process. Furthermore, as a size and a circuit line width of a semiconductor device are decreased and a structure of a semiconductor becomes more complicated, it is difficult to apply a double thin film structure to recent nano-scale semiconductor devices, and the double thin film structure causes a significant difficulty in a copper electroplating process. Moreover, the double thin film structure increases a resistance of a copper wiring.
Since a Co metal thin film contains a polycrystalline material, a diffusion path of copper is formed along a grain boundary, degrading diffusion barrier characteristics of the Co metal thin film. Ru, which is a type of a precious metal, makes it difficult to reduce a cost. Furthermore, since an oxidizing agent such as oxygen is used as a reactant, oxidation of a thin film may occur at the time of associating with a related process. In the case of copper, surface oxidation rapidly occurs.